Railway traffic controlling apparatus



May 1, 1945. J. J. VAN HORN RAILWAY TRAFFIC CONTROLLING APPARATUS 2 Sheets-Sheet l Filed May 8, 1943 fiqwxu v H Q m a ww d m m T m m g MEN M1 1 m F FEW Z RN M Y u 5% QM ma J E NEE E 5% m NW, m mw w b ww fiwkw IL mm mm Q E QNMUM wwwfim w y 1945- J. J. VAN HORN 2,374,792

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 8, 1943 2 Sheets-Sheet 2 Fig. 2.

K b N El MN Q a E a g INVENTOR Jam and. Vazz H0212 b HIS ATTORNEY .causes'the transmission 7 the other end if the stretch is then unoccupied.

Patented May 1, 1945 T OF 'FlCE' RAILWAY TRAFFIC CONTROLLING APPARATUS James J; Van Horn,

The Union" Switch Pittsburgh, Pa., assignor to & Signal Company, .Swissvale,.-l?a., acorporation of Pennsylvania I ApplicationMay 8, 1943, Serial No. 486,190

.6 Claims. (01. 246-3) My invention relates to railway traffic control- ]ing apparatus and more particularly to apparatus for the control of trafilc in a single track, twodirection system wherein centralized trafiic control or other suitable manual control is used for establishing the traffic direction. A distinguishing feature of my system is that it is of the normally deenergized coded track circuit type which dispenses with all control line wires except for the C. T. C. coded line circuit if C. T. C. control is used.

"One object of my invention'is to provide a normally deenergized track circuit system of signaling for traffic moving in either direction on a single track, employing ,no control. line} wires 5 Another ob,-

for the usual signaling functions. ject of my invention is to provide signal control by means of track circuit code, employing'ma'ster and feed-back codes for this purpose, the source of master code being located at e the stretch. A further object of my invention is to provide an unoccupied block indication and. a check of the stop indication of the opposing signal. A still further object is to prevent the removal of track circuit code while the stretch is occupied so that'energy will be available for restoring the following stick relay to its normally deenel'gized condition, thus causing the track circuits to'become normally deenergized. v

I I accomplish the foregoing objects by applying master code at one end of the stretch only, which of a feed-back code from Presence of these two codes makes it possible to clear the eastbound or the westbound headblock signal, as desired. By polarizing the feed-back code, an adequate unoccupied block indication for both ends of the stretch is provided. Also, by controlling the stick circuit of the'relay which deenergizes the track circuits and which I shall designate a power ofi relayover a back contact of the track relay repeater, it is possible to restore the stretch to its normally deenergized condition after the stretch is unoccupied, but not before. e

I shall describe two forms of apparatus embodying my invention and shall then point out the novel features thereof in claims.

Fig. 1 of the accompanying drawings is a dia-' grammatic view showing a single track, two direction signaling system embodying my invention and employing neutral feed-back code. Fig. 2 is a diagrammatic view showing a modified form of a portion of the system shown in Fig. 1, cmploying polarized feed-back code. f

one end only of 1 v Similar reference-characters refer to similar parts in each of the two views.

Referring to Fig. 1 of the drawings, I have shown a stretch of single track D-H divided into track circuit sections by means'of the usual insulated rail joints at locations D, E. F, G and H. Location F'is a 'cut-sectionlocation'forthe normally deenergized coded'track circuits EF and The normally energized short track circuits D Eand G'Hat' the respective headblock signal locations serve the usual detector function and permit following under a clear or a permissive signal indication.

At each end of the stretch 'is a' field station unit connected with the usual C. T. C. line over which control impulses arersent out from a.- suitable C.*T.'C. control location or oifice, andover which the block unoccupied indication and "the stop indication of the opposing signal arealso transmitted from the field to the ofiice. The C. T. C. apparatus, of itself, formsno part of my present invention and it is unnecessary to show this apparatus in detail for an understanding of my invention. Reference maybe had to Letters Patent of the United States No; 2,229,249 granted to L. V. Lewis on January 21,1941, for a detailed description of a C. T. C. system such as can be used herein and I have used the same reference numbers as are used in that patent to designate certain'terminal wires of thefield station' unit which perform analogous functions.

The headblock signals 2 and 4 at the ends of the stretch control the entry" of eastbound and westbound trafiic respectively'into the stretch, and the indications of these signals are controlled by meansof track circuit codes which, in turn;

are controlled by the field station C. T.'C. apparatus. The master code which is applied at 10- cation G and is transmitted 'westwardly provides block control for code which is applied at location E and is transmitted eastwardly providesblock control for signal 4. The track circuits EF and F G become energized only after asuitable code is transmitted C. line to energize terminal 82 of the field station unit U2 or U4 in order to pick up the respective traffic control reIay ZC or 40, according as the tralfic direction being established is eastbound or Westbound. f f

The apparatus at the right-hand end of the stretch includes two signal control relays MD and 4BH,-the first of which controls the upper unit of signal 4 whereas the second controls the lower unit of this signal, as indicated in the I analogous controlcircuit for signal 2 in the drawmoves to be made'either signal 2, whereas the feed-back ings. These two relays are controlled over a circuit which includes contacts of the detector track relay 4TB, directional stick relay 48R, code checking relay 4TP, and the C. T. C. controlled traffic direction relay 4C or 4P, depending upon whether the operator desires to have signal 4 display a clear or a permissive indication,- respectively. The relay 48R is not shown in the drawings but is controlled in substantially the same manner as the relay ZSR.

The apparatus at the signal 4 location also in cludes the code selecting relay 4Rwhich determines whether the track stretch will receive" 180' or 75 master code, and it also includes the C. (3. controlled normally deenergized ing relay PG which maintains code-on the track power-govern circuits during such time only as required by Relay CTM is the code recupancy by means 'ofia stick circuit'for relay PG which includes" the back contact'ti of relay 4TP and the front contact 6 of relay PG. The reason for including'the back contact 5 in the stick circuit is to retain relay' PGrenergiz'ed so that the operator cannot remove code from the track cir' cuit during occupancy.- Were'such removal possible, track circuit energy would not be available for energizing the relays necessary 'for interrupting the stick circuit ofv the directional stick relay after a'train vacated the stretch. v

The apparatus at the west end of the stretch is generally similar to that at the east and except for the absence of code transmitters at this location and the presence of decoding apparatus which distinguishes 'betweenthe two codes. The code transmitting relay 'at this location is the impulse relay ZBZ'which transmits the feed-back code." The cut-section apparatus includes the usual apparatus, for repeating normal and feed-back codes over the cut-section location. a V 1 In explaining the 'operation,'I shall assume that at location F track "relays and associated the stretch is in itsnormal, 'unoccupiedcondition so that the track circuits E-'-F and F-YG are deener'gized'and the signals 2 and 4 are at stop. a If the operator now wishes to display a clear aspect on signal 2 for an eastbound move, he will trans mit a suitable code from the control olfice over th' C. T. C; line so as to energize'terminal 82 of the field station unit'UZ and thereby pick up the eastbound clear control relay 2C. The operator will also send out a second code to the field station unit U4 at the in order to energize terminal '84 so'as to pick up the power-governing relay PG'and so energize the track circuits by means of code. Pick-up of relay PG closes a circ t for each of the code transmitters ICT and l, and also'closes a circuit for 'relay lRpver the back-contacts 8, 9 and H) of relays 4S3, and 4AD, respectively. Since signal'4is atstop', the signal control "relays 4BR and 4A1) will be deenergized. The directionalstickrelayi$fiwill also be deenergized since the stretchis assumed I indication of signal 2.

other end of the stretch T over the front contact picked up so as to H and 2'2 of relays2'SR and to be vacant. Accordingly, the energizing circuit for relay 4R will be closed and this relay will be picked up. Since of relay 4R. is closed, relay CTM will be coded at the code rate over contact 12 of the code transmitter NOT. included in the circuit for relay CTM is the front contact '13 or track relay 4TB; which prevents the application of code to the section, should a train be occupying the de- ','tector track circuit G-H.

If, instead of energizing relay 20 to cause the display of a clear indication by signal 2, the operator had'energized terminal 8| of field unit U2,

permissive :control relay ,2P would have been energize relay 23H and thus cause the display of this signal.

Relay'CTM in following 180 code will cause ourrentoi this code to be periodically supplied from battery TB over the front point of contact M to the track c'ircuitF-G.' At location F track relay"4A will follow this code. being nergized over the back point of contact 15 of the impulse relay 4A2, and will repeat the code into track circuit E-F 'o-ver' the front Thereup'on track relay code, being energized over the back point of contact 3.0 of relay "ZBZ, and will energize the repeatin'g relays 218T and ZTP over obvious circuits. Re1ay.2BT is a slow acting relay which remains energized as long as relay 21 is following'code, and relay ZTP is a cod'e're'pcating relay which energizes the decoding transformer DT and its associated decoding equipment in the usual manner. In the case of long track circuits, the track relay 2T will ordinarily be a sensitive single-contact irelay so that "a repeater relay such asZTPhavirig the'ne'cessary' number of contacts will be required. Relay ZZBT will be energized onlyw'hen'relay 2T is following code. Consequently; front contact 11 will be closed and will apply energy to the decoding apparatus at such times only as code is present in the track section, in anticipation of the entry'oi a train. At all other times, the decoding apparatus will be dee-nergized to conserve power.

Since the track relay 2T is responding to 180 codeunder the assumed condition, both decoding relays H and D will be picked up. Relay H is picked up on either 180 or '75 code, whereas relay D responds only to 180 code because of the presence of the resonant rectifier unit iflflDU in its energizing" circuit. The pick-up of relay D, since relay 26 remains picked up over its stick circuit, closes the energizing circuit tor the signal control relay 2AD which controls the clear The circuit for relay 'IAZD includes front contacts 18, i9 and! of relays 2TB, D-and 2C, respectively, and, back contacts ZBH. Front contact i8 checks that the'section DE is unoccupied, whereas back contacts 21v and 22 check that the directional stick relay 2553. is released, as it should be when; the stretch is vacant, and that signal 2 is not displaying a permissive indication.

Assuming for a moment that' the stretch is occupied by an eastbound train, when the train enters the track circuit D --E the directional stick relay ZSR will be picked up over a. circuit which includes the back contact-23 of relay 2TB and the front point of contact 24 of relay 2A1). "A stick circuit for relay 28R will now beback contact 250i relay oint'of its contact I6.

come eficctive over the 2TB. and the fr'ontco tact :26 of relay 25R... The

latter relay, when energized, makes it possible the front point of contact H a permissive indication by 2T will also follow the V the circuit for the impulse relay contacts-21, 28 and 29 of relays- 2AD, ZBH and ZSR, respectively, and since relay HR is also energized, the circuit for'impulse relay 232 will be closed so thatthis relay will be periodically energized from the decodingtransformer in well-known manner and willoperate contact 30 periodically to supply 'feed-back codeover' the front point of this contact to'thetrack circuit E---F'. 'I'l'iis code-is supplied during the off intervals inthe normal or master code'to which the relay 2T is responding, and operates the relay 2AT-at the other endofthetrack circuit. Relay ZAT will follow the feed-back code and will maintain relay ZRGA energized so that 4AZ will be' closed at this time. Accordingly, relay'4AZtwill transmit afeed-back code over the front point of its contact l5 and over the section F G; so as to produce code operation of relay 4T onfeed-back code. Relay 4TP will therefore be-ener'gized.

Energization' of relay 4TP indicates thatthe track stretch D-I-I between the signals 2 and 4 is unoccupied; that signal 2 is at stop; and that the directional stick relay 23R is deenergized.

' Signal 4 may now'be cleared. -'If,"instead' of causing signal 4 to display. aclearindication, it is desired that this indication be a permissive one, the operator-may causerelay 4BH to become energized over a circuit which includes front contact 3| of relay 4TP, back contact 32 of relay 4AD; and front contact 33 of the code controlled relay 4P which repeats thepermissive position of the C. T. C. control lever (not shown) for signal '4 in the usual manner. v

A westbound train accepting signal 4'and en-- tering the track circuit G-H will cause the directional stick relay 4SR to become energized over a circuit similar to that shown and-described for relay'ZSR. Relay 4SR will there-'- after remain energized over its stick circuit during occupancy of the section D-H. i

With signal 4 displaying either a clear. or a permissive indication, relay4R will be deenergized' because its circuit will be open at back contact Ii! of relay 4AD or at back contact 9 of relay 43H, respectively. Accordingly, 75 master code instead of"1 80 will be supplied to the track stretch over the back point of contact ll of relay 4R. The track circuit apparatus in respending to75 code will cause relay D atthe west end of the stretch to became deenergized so that only relay H will now-be energized. With relay D deenergized, signal Zcannot display a clear proceed indication.

With signal 4 at stop and relay 4SR energized,

relay 4R will be deenergized because its circuit will be open at back contact 8 of relay 4SR. Accordingly, 75 mastercode will beapplied to the track stretch until the westbound train vacates the stretch whereupon feed-back code will be received from the west end to energize relay 4TP. The control network for relay 4SR is identical with that for relay 2SR at the other end with the exception that the back contact of relay D in the stick circuit is replaced by a back contact of the relay 4'I'P. Energization of relay 4TP .will open the stick circuit of relay 4SR whereupon relay4R will be energized to apply 180 master code to the stretch. Relay'PG may plied. If the feed-back now be deene'rgiz'ed so as to deenergize the coded track circuit apparatus.

As long as master code is being tionG and the stretch remains unoccupied, one or the other of relays D and H will be energized so -that an energizing circuit may be established for terminal 9| of the fieldstation unit U2 to provide an unoccupied block indication. This circuit includes one or the other front contact 34 or35 of relays H and D and is checked over front contact 36 of track relay ZTR. At the other end of the stretch, the clear block indication may be similarly obtained through the energization of terminal SI of field station unit U4 over front contacts?! and 4| of relays 4TP and 4TR. This, however, .is not so satisfactory an unoccupied indication as that provided atthe other end of the stretch because relay 4T]? will be deenergized when signal 2 is cleared by means or the G. T. C. control, so that the occupied block indication will be given prior to the actual entry of a. train into the section. I

"If it isdesired to provide an unoccupied block indication at the east end which will be as satisfactory as that obtained at the west end, then applied at locathe apparatus of Fig. 2 may be used. Referring to Fig. 2, the apparatus of this figure is similar to that of Fig. 1 feed-back code is now polarized. Accordingly, when relay ZRG which repeats the stop position of signal 2 is picked up, the feed-back code will be of normal polarity-whereby relay-ZATA will operate its contacts to the left,-as shown, and relay 2AT will respond to the impulses of feedback energy supplied over the rails of section Relay ZAT is-abiased polar relay which picks up on current of one polarity only, current of the other polarity causing its armature who held firmly in'the deenergized position. In this way, contacts of relay 2ATA to insure that the re-' sponse of the latter relay is in agreement with the polarity of the feed-back code being supthen relay ZRGA will decoding transformer and over contact38 of relay 2ATA closed in its left-hand position and will establish connections to cause impulses of feedback energy .of normal polarity to be supplied from the feed-back battery'to the rails of sec tion F-G as a result of operation of1relay 4AZ. Thefeed-back energy of normal polarity'sup plied to the rails of section F-G causes the-confacts of relay 4BTA to occupy their left-hand 'or normal position, so that on coding operation,

through the'de of relay 4BT energy is supplied coding transformer to relay 4RGA and its contact 39 is picked up to establish a, circuit lead ing to terminal 9| tion unit and thus cause a block clear indication to be transmitted to the 'oflice. I

When signal 2 displays 3, proceed aspect or the directional stick relay ZSR is energized, thenrelay ZRG will also be deenergized so that the feedback code supplied to the rails of section'E-F will be of reverse or negative polarity and will cause the contacts of relay right-hand or reverse positions so that on code following operation of relay 2AT energy is supplied from .the decoding transformer over reverse or right-hand polar contact 38 of relay 2ATA to relay 2BP and its contacts are picked up. When relay 2BP is picked up, the feed-back battery is-connected with the rails of track'sec tion F-G in such manner that on coding operawith the exception that the relay 2AT- can be checked over the code is of normal polarity, be energized through'the of the C. T. C. system field sta- 2ATA to occupy their .Ielay PG to .maintain over which trafllc between the first oirelayABTA to occupy their right-hand; posltion so that on coding operation or relay-4B1 energy is supplied from the decoding transformer to relay 4BP.:and its contact 40: establishes a circuit to energize terminal alqof theC. T. C. system field station unit and cause it totransmit a block clear indication tothe oflice.

The relay ARGA employed in the modification shown in Fig. 2 may be substituted for the relay ATP. in the circuits of the relays 4AD, 43H and PG inthe system shown in Fig. 1. The relay 4RGA i eenergized when signal 2 is cleared or when the stretch is occupied and therefore ins.

sures. that at these times relays 4AD and 43H are both'released, to maintain the display of the stop indication by signal- 4, while a thesetimes relay IRGA also maintains'the stick circuit of the supply of track circuit energy to the track stretch. After signal 12 hasbeen cleared, but while the stretch is still unoccupied, the relay 4B]? is picked up to main tain the block clear indication.v From the foregoing, it will be apparent that theapparatus of Fig. z provides an unoccupied block indication at each end of the stretch which is: independent of'the indicationwhich the en.- trance signal at that end may be displaying at the time;

Instead of. control apparatus, it. is apparent that direct manual control such, for. example, as a signal lever at eaehend of the. stretch may be usediii desired to obtain the advantageous operation of the apparatus herein disclosed. In either case, thezmanual block signals will have full track cirsuit control thereof and will provide complete opposing signal protection. Since the signals themselves involve only safety circuits fortheir control, the auxiliary apparatus such as the 0.1.1, 0. equipment need theis-afety type since this equipment merely supole-merits the signal control and provides for the transmission of the-signal indications. It will be. apparent; also, that I. have provided a normally deenergized coded track circuit system-inwhich it is not necessary to cut oil the. trackv circuit energy at bothends or the stretch as in other systems, it being sufficient to cut off this energy. at hut'one end in order to restore the system to its normally deenergized condition following the exit of a train. By polarizing the ieedbac.k code, I provide. an accurate unoccupied block indication at' either end of the stretch;

Although I have hereinshown and describedonly two forms of apparatus embodying mypinvention,.it is understood that various changes and modifications may be made therein. within the scope of the appended claims without departing from the spirit and scope of my invention. 1 Having thus described my invention, what. I .claimjsj: v i

1. In combination, a section of railway track may move, in either direction and th second end thereof, a power-governing relay at the-first end ofsaid section having contacts movable between a first and a second position, means for at times moving the contacts of said power-governing relay from their first to their second position, means effective when th ontacts of said .powensoverni g r lay arein their second-position to cause master code ener y to be supplied to the rails of 'saidtrack employing C. T. or other remote section at-thefirst end thereof, means responsive to receiptuo'f master code energy at the second end of said section for supplyingimpulsesof feed-back energy to thera'ls of said-section at the second endthereof, a signal governing en-v tranceof traflic into said section at thefirst end thereof; and means responsive to receipt of feed.- hackcnergy over thesection rails at thefirstend thereof for controlling saidsigna i --'*2,-In; combination, a section of railway. track over. which. traflic, may-move. in either direction bctwoonthe first and the second endthereof, a'

powersgoveming relay at the first, end of said section havingzcontacts m v e b tw en a. fir t and a-second position,'means for at times moving thercontactsoi said ower-governing relay from their first. to their. second. position, means 'effec tive, when the contacts of said power-governing rclavare inthcir second position to cause master code energy to be supplied to the rails of said track. section at ponsve to receipt of master code ener y at'the second end ofysaidsection for supplying impulses of feed-back ener y to the rails of said section at 'the 'second. end thereof, a signal governing entrance of traffic into-saidsection t the firstend thereof, means responsive t receipt oi feed-back energy. over the section rails atthe first-end thereof .for controlling said signal, and. means .efqfectivepnly when feed-back energy is; being res ceived at the first endof saidsection for moving thecontacts of saidpower-governing relay from I their second to their first position.

not necessarily beef I ti-ve when thev contacts 3. In: combination, a secti -n of. railwaytrack over which trafllc may move in either direction between .the first and thesecond endthereof, a .power goverm'ng relay atthe first end of said section having contactsmovable between a first and a second positionmeansfor at times moving the contacts-0f said power-governingrelay from their, first to their second position, means efiecof said power-governing relay are in their second position to cause master code energy-to be supplied to the rails of said track section at the: first end. thereof, means responsiveto receipt of master code energy at the second end of said sectionfor supplying impulses of feed-back energy to therails of said section at the second. endthereoi, a first signal governing v entrance of trafilcinto said section at the f rst end thereoi,- ,tsecond Signal governingv entrance of traffic into said section at the second end thereof, meansresponsive to receipt of .master code energy over thesection rails at the second end of said section. for controlling saidsecond, signal, and means responsive to receipt of, feed-back energy over the section rails at the first end thereof. for controlling said first signal; 7 p i. in combination, a section of railway track over which traffic may move in either direction between the first and the. second end thereof,

a power-governing relayat the first end of said scction'having contacts rnovable between a first and. asecc o it n, m s f at times mo n the contacts of saidpower-goyerning relay from their, first totheirsecond position, means effec tive when the contacts of said power-governing relay arein their second position to cause master code, energy to besupplied. to the rails-of said track section at thefirst endthereoh a first sig pal-governing entranceo-fftrafiic into said section at the. firstend theneoi, a second signalgove erning entraneof tr-afiic into said section at the secon end. th conmeans sponsive to. receipt oim s r..sode energy ove thesectien irailsat .the first end thereof, means re-.

at the first end thereof for controlling said first signal.

5. In combination, a section of railway track over which trafiic may move in either direction between the first and the second end thereof, a power-governing relay at the first end of said section having contacts movable between a first and a second position, means for at times moving the contacts of said power-governing relay from their first to.their second position, means effective when the contacts of said power-governing relay of a first or a second type according as said second signal is displaying its stop or a permissive indication, means responsive to receipt of feedback energy of said first type only over the section rails at the first end thereof for controlling said first signal, and control means responsive to receipt of feed-back energy of either type over the section rails at the first end thereof.

6. In combination, a section of railway track over which traific may move in either direction between the first and the second end thereof, a

- first signal governing entrance of traffic into said are in their second position to cause master code energy to be supplied to the rails of said track section at the first end thereof, a first signal governing entrance of trafiic into said section at the first end thereof, a second signal governing entrance of trafilc into said section at the second end thereof, means responsive to receipt of master code energy over the section rails at the second end of said section for permittingsaid second signal to display a permissive indication, means responsive to receipt of master code energy over the section rails at the second end of the section for supplying to the rails of said section at the second end thereof impulses of feed-back energy section at the first end thereof, a second signal governing entrance of traflic into said section at the second end thereof, means for supplying to the rails of said section at the first end thereof master code energy of a first or a second type according as said first signal is displaying its stop or a permissive indication, means responsive to receipt of master code energy over the rails of said section at the second end thereof and selectively responsive to the type of such energy for permitting said second signal to display a first or a second permissive indication according as Said master code energy is of said first or said second type, means responsive to receipt of master code energy of either type over the section rails at the second end thereof for supplying impulses of feed-back energy to the section rails at the second end thereof, and means responsive to receipt of feed-back energy over the section rails at the first end thereof for controlling said first signal.

JAMES J. VAN HORN. 

